Propellant explosive



. T all whom it may UNITED STATES OSWALD SILBEBBAD, OF BUCKHUBST HILL,

7 i in"... w a

PATENT OFFICE.

ENGLAND.

PROPELLANT EXPLOSIVE.

No Drawing.

concern:

Be it known that I, ()SWALD SILBERRAD, consulting chemist, a subject of the King of England, and residing at Buckhurst Hill, in the county of Essex, England, have invented certain new and useful Improvements in Propellant Explosives, of which the following is a specification.

My invention relates to explosives of the propellant class and has for its object the production of propellants which give no flame and little smoke when fired in guns or howitzers of a suitable caliber and design,

' or rifles or shot guns.

my invention relates to the production of a flameless powder" of such properties that when made of the required size the correct charge will when fired in a suitable weapon give the present service velocities without flame and at the same time produce little if any more smoke than is produced by the so called smokeless powders at present in use. y the term suitable weapon I include an rifle or shot gun at present in use, any howitzer at present in use up to and including 6", and/or any gun at present in use up to and including the 3.3". A flameless powder is not flameless if burned in the open, nor is it flameless if fired in guns where the cooling effect due to the energy absorbed by the shot is insufficient to reduce below their ignition point the temperature of the gases evolved upon the firing of said propellant in said guns. It will be observed therefore that a flameless powder as herein defined is not necessarily flameless if fired in guns of larger caliber than those specified in above definition or at pressures hi her than the normal working pressures. nd throughout this application I use the term flameless powder to denote a propellant which will give the aforesaid results whether said powder be flameless in guns and/or howitzers of larger caliher or not, and include propellants which give the aforesaid results either alone or with the admixture of any given proportion of any given propellant which when fire alone produces flame.

Heretofore all attempts to obtain this effect have been based on the use of salts o metals such as the carbonate or bicarbonate of sodium or potassium or resinate of so- In particular dium or calcium: By this means powders have been produced which are fiemeless i Specification of Letters Patent.

Application filed September 10, 1919.

Patented Aug. 1'7, 1920.

Serial No. 322.947.

some of the smaller are, however, of very enormous amount of produced.

I have discovered how to produce a flameless powder without the introduction'of any metallic salts or any compound which leaves a relatively non-volatile residue; in short, the flameless propellant which I produce bears a similar relationship to the known fiameless powders as the present smokeless powders bear to the old black powder.

My invention therefore relates to the production of a new article of warfare and commerce, namely, a fl-timeless powder as hereinbefore defined.

As a result of a very exhaustive study of the interdependent equilibria which control the composition of the products of the autocombustion of propellants under the conditions pertaining in artillery practice, I have discovered that the aforesaid result can he arrived at by suitably raising the ratio of guns. Such powders ittle use owing to the smoke simultaneously I groups 0 0 groups, and

- l ing also a preponderance of H-(i-JJH groups as are intended to be included herein, such compounds are starch, mannite, sugar, glucose, cellulose, lignocellulose, cellulose acetate and the like. From the above data it will be simple to select other suitable compounds though of the aforesaid I find that starch is the most suitable and produces a powder which as well as being possessed o the best keeping properties also gives rise to less smoke than any other flamelesspowder I have been able to produce an far less than anything heretofore produced; I therefore prefer to use starch.

Further, I have discovered that in order to -render the fiameless powder as smokeless as possible it is necessary to incorporate the starch or the like into the powder and that if said starch or the like be merely added to the finished propellant the interaction of the said starch or the like on autocombustion is not complete and much carbonaceous matter separates as smoke on firing. ()n the other hand I find that quite satisfactory results can be obtained by lncorporating an excess, say for example, twice the quantity required of said starch or the like with any given propellantimixture and then making up charges or cartridges of a mixture of this product together with any ordinary propellant or smokeless powder in the desired proportions, namely in the above example in equal proportions, each propellant being of the desired size. From this it will be observed that it is not necessary for the starch or the like to be evenly distributed throughout the entire charge, but that the charge may be made up of a mixture of a propellant containing an excess of starch or the like with one containing a deficiency or none at all, as for example any of the smokeless powders at present in use providing always that the quantity of starch or the like in the entire charge be such that the temperature of the gases emitted from the muzzle is below their ignition point as hereinafter set forth.

In carr ing my invention into effect, therefore, l prefer to use starch and to incorporate said starch with any suitable propellant material or mixture which without such addition would produce a propellant such that if fired in the aforesaid weapons would produce flame.

I have found that the quantity of starch or the like to be added depends on the pyrometric value of the original propellant, material or mixture used and must be suflicient to reduce the temperature of the gases emitted from anv given gun to below the ignition point 0 said gases when the resultant product will be found to be a flameless powder as hereinbefore defined. The quantity can therefore be calculated by those familiar with thermod namics and internal ballistics; thus, using .allard and Le Chateliers figures for the specific heat of gases, we find that the pyrometric value of M. D. cordite under conditions similar to those pertaining in artillery practice is approximately 2300 C, hence to produce a fiameless powder as hereinbefore defined using M. D. cordite as a basis it is necessary to add approximately 16 parts of starch to 100 parts of the ingredients of which M. D. cordite is composed. Applying the same considerations to other powders in use we arrive at the following figures as representing the quantity of starch that should per 100 parts Mk. I.

ity guns of larger caliber, but that the specific pressure or power of the powder will be lowered by such an addition, so that it may be necessary to increase the size of the chamber of such large guns in order to take the increased charge; at the same time, however, the erosion is greatly reduced. Thus we arrive at the following figures:

,grga H 0 k 8 Ho's 0 n) o 3. $3 "Eu Q 55 U 5 9 the :1 Powder. g gg .S-" H58 s35 rig..-

g 5 T1" u g 8 sss sass me it o is y M. D. cord'ite 17.10 1025 100.0 M. D. corditc+40 parts of I start-h 11.65 660 11.8

It must, however, be admitted that calculations of this nature are exceedingly complex, so that those less skilled in the art may be desirous of arriving at a close approximation by making use of the fact that for propellants of a similar nature the pyrometric value will be approximately proportionate to the calorimetric value; for the use of such the following table is appended whereby they can by the simple process of exterpolation arrive at a very close approximation to thequantity of starch that should be added to any propellant mixture or basis of any given calorimetric value:

a s a., E? its 5, m a B 35 E E as am '5 o s 4- Us a- 3.5 Nature or propellant mixture used. Bag: g g '6 t E a g gle. sass a 0 g, 3 gs? E5 a a as EM 0 1 American pyrocollodion 890 7.0 Norweman ballistite 995 14.0 Walsrode 10!) m 15. 5 M. T cordite 1025 15.0 Mk. I. cordite. 12 0 28. Sportinu hallistite. I295 Italian bfilliStitfl i i 1325 33.0

size and dried in the usual manner.

erosive than any Throughout this specification and in particular in the claims at the conclusion thereof, I use the term nitrocellulose to include any variety of nitrocellulose, namely the variety insoluble in ether-alcohol commonly known guncotton and also the soluble variety known as soluble cotton or pyrocollodion. In carrying my invention into effect it is merely necessary to incorporate the material which goes to make up the propellant basis in the presence of a gelatinizing agent and preferably that normally used for such mixtures as constitute the basis, for example acetone where guncotton or insoluble nitrocellulose is present and ether alcohol where soluble nitrocellulose or pyrocollodion is present, and to incorporate, preferably after gelatinization is complete, the necessary quantity of starch into the dough then to form the dough into the desired shape and size and dry the product in the usual manner. Thus, according to one example in which I use a mixture of nitrocellulose, nitroglycerin and Vaseline as the basis I proceed as follows:

307 lbs. of nitrocellulose containing 13.3% nitrogen is mixed with 4.40 lbs. of nitroglycerin and the mixture rubbed through a sieve in the usual manner: This mixture of nitrocellulose and nitroglycerin is then charged into an incorporator, preferably of the Werner Pfleiderer type, and 100 lbs. of acetone added and the mass incorporated for 6 hours; 39 lbs. of Vaseline and 214 lbs. of starch in a fine state of division are then added; the whole is then incorporated for a further period of 2 hours; during the period of incorporation 871 lbs. of acetone is added as required, after which the dough is pressed into cords or tubes of, the desired The obtained will be a fiameless hereinbefore defined, and less known artillery powder and far more powerful than any of the less erosive powders now in use, its properties in these respects being as set forth in tlie following table wherein the power and erosive properties of modern artillery powders are also set forth for comparison, taking cordite M. D. as 100:

propellant so powder as I u A O a}; a r:% 2% o m w :2 5 Powder. E g g 8 55:1 3' m E, o 010 m [=3 0-: New nameless powder 46. 6 15. French B. N 50.0 14. 90 American pyrocollodion 51.0 14. 80 Norwegian ballistitc 96. 5 lo. 85 Cordite M. I). 100.0 17. 40 Corditc' Mk1... 173.11 19. 25 Italian .iallistite 218. 0 18. 45

According to another example in which I plosives,

ufacture a product containing 10% more starch, than 18 necessary to produce a flameless powder I proceed as follows:

(300 lbs. (dry weight) of moist soluble nitrocellulose is freed from water by displacing said water with alcohol in the usual manner, after which the excess of alcohol is removed by means of hydraulic ressure, also in the usual manner. The solilble nitrocellulose containing about 200 lbs. of alcohol is then transferred into a suitable incorporator and incorporated for about (5 hours during which time an amount of ether equal to about twice the weight of the alcohol originally left in the charge is added. After this 114 lbs. of starchis added together with a further addition of solvent if required and incorporation continued for a. further 2 hours. The dough so produced is then formed into the desired size and shape and finally dried in the usual manner. The resulting product will be found to be flameless not only in the weapons above mentioned but also in guns and howitzers of somewhat larger caliber; it is, however, low in power so that I prefer to use it admixed with an ordinary smokeless powder which without such admixture would produce a flame and to use a quantity of this new product equal to ten times the weight of starch required as hereinbefore set forth, as for example- (a) American pyrocollodion" 100 New product 7O (1)) \Valsrode 100 New product 155 Such mixtures will be found to be fiameless powders as hereinbefore defined.

Having thus described my invention what I claim as such and desire to secure by Letters Patent is 1. In the manufacturemf propellant explosives, the addition of starch to the basic propellant, in such quantit as to reduce below their ignition point t 1e temperature of the gases evolved upon the firing of the said propellant in suitable guns as hereinbefore set forth.

2. In the manufacture of propellant explosives, the addition of starch to the basic propellant,in quantity greater than is nec essary to reduce below their ignition point the temperature of the gases evolved upon the firing of the said propellant, in suitable guns as hereinbefore set forth.

3. In the manufacture of propellant exthe addition of starch to the basic propellant in such quantity as to reduce below their ignition point the temperature of the gases evolved upon the firing of the said propellant, in suitable guns as hereinbefore set forth, said starch being incorporated with the material of said propellant in presence of a gelatmizing agent.

4. In the manufacture of propellant explosives, the addition to the basic propelant of an organic com ound containing a preponderance of H- OH groups, in

such quantity as to reduce below their ignition point the temperature of the uses evolved upon the firin of said prope lant in suitable guns as hereinbefore set forth.

5. In the manufacture of propellant explosives, the addition to the basic ropelant of an organic com ound containing a preponderance of H- --()H groups, said compound being incorporated with the material of said propellant in presence of a gelatinizing agent, and in such quantity as to reduce below their ignition point the temperature of the gases evo'lved u on the firmg of said propellant in suita le guns as hereinbefore set forth.

6. In the manufacture of propellant explosives, the addition to the basic propellant of organic com 'ounds containing a preponderance of -C-OH groups, in such quantity as to reduce below their ignition point the temperature of the gases evolved upon the firing of the said propellant in suitable uns as hereinbeforeset forth.

7. In t e manufacture of propellant exlo'sives, the addition to the basic propelant of organic compounds containing a preponderance of H-C- OH groups, said compounds being incorporated with the material of said propellant in presence of a gelatinizing agent, and in such quantity as to reduce below their ignition point the temperature of the gases evolved upon the firing of the said propellant in suitable guns as hereinbefore set forth.

8. In the manufacture of propellant explosives, containing nitroccllulose, the addition of starch to said nitrocellulose in such quantit as to reduce below their ignition point t e temperature of the gases evolved upon the firing of the said propellant in suitable guns as hereinbefore set forth.

9. In the manufacture of ropellant explosives, tion of starch to such nitrocellulose in such quantity as to reduce below their ignition point the temperature of the gases evolved upon the firing of the said propellant in suitable guns as hereinbefore set orth, said starch being incorporated With said nitrocellulose in presence of gelatinizing agent.

10. In the manufacture of propellant explosives conta'ining nitrocellulose, the addition to said nitrocellulose of an organic compound containing a preponderance of H-COH groups, in such quantity as to presence of containing nitrocellu osc, the addi-,

reduce below their ignition oint the temrature of the gases evolve upon the firing of the said propellant in suitable guns as hereinbefore set forth.

11. In the manufacture of ropellant explosives containing nitrocellu ose, the addition to said nitrocellulose of an organic compound containing a preponderance of H-G-OH grou s, said compound being incorporated wit said nitrocellulose in presence of a gelatinizing'agent and in'such quantit as to reduce below their ignition point t e temperature of the gases evolved upon the firing of the said propellant in suitable guns as hereinbefore set forth.

12. In the manufacture of propellant explosives containing nitrocellulose, the addition tosaid nitrocellulose of or anic comppunds containing a prepon erance of -C--OH groups, in such quantity as to reduce below their ignition oin the temerature of the gases evolve upon the fir m of the said propellant in suitableguns as hereinbefore set orth.

18. In the manufacture of ropellant explosives containing nitrocellu ose, the addition to said nitrocellulose of or anic comounds containing a prepon erance of -C-OH grou said compounds being incorporated witli said nitrocellulose in a gelatinizing agent and in'such quantitl as to reduce below their ignition point t 0 temperature ofthe evolved upon the firing of the said propellant in suitable guns as hereinhefore set forth.

14. The manufacture of a flamelese powder as hereinbefore defined by incorporating a com and with a preponderance of H-CO cups with nitrocellulose and with a elatinizin agent substantially as hereinbe ore deecri' d.

15. The manufacture of a flameless powder as hereinbefore defined by incorporating a co pound containing a preponderance of H'-COH groups wit mixtures containing nitrocellulose and with a gelatinizing agent substantially as hereinbefore described.

16. A flameless powder as hereinbefor defined composed substantially of a mixture of nitrocellulose 30.7% glycerin 44%, vaseline 3.9% an 21.4% as hereinbefore described.

In testimony whereof I have aflixed my signature in presence of two witne "s.

OSWALD SILBE l AD.

starch Witnesses:

VIc'ron F. FEENY, Cram J. Fnnnr.

nitro- 

